Conventionally, carbon fiber composite materials have been used in structures such as aircraft structures where weight reduction is required.
An example of a method used for monitoring the resin curing of carbon fiber composite materials is a method using an optical fiber provided with an internal grating sensor, such as the method disclosed in Patent Literature (PTL) 1.
Members of carbon fiber composite materials are generally joined together using fasteners such as rivets or bolts.
When joining members together, using an adhesive is optimal in terms of factors such as weight reduction and operational efficiency, but evaluation of the bond quality is necessary. Evaluation of the bond quality is performed by bonding the members together with an adhesive, and then conducting an ultrasonic flaw detection inspection or the like.